<?php

if (! defined ( 'BASEPATH' ))
	exit ( 'No direct script access allowed' );
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2008 - 2011, EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------


/**
 * SHA1 Encoding Class
 *
 * Purpose: Provides 160 bit hashing using The Secure Hash Algorithm
 * developed at the National Institute of Standards and Technology. The 40
 * character SHA1 message hash is computationally infeasible to crack.
 *
 * This class is a fallback for servers that are not running PHP greater than
 * 4.3, or do not have the MHASH library.
 *
 * This class is based on two scripts:
 *
 * Marcus Campbell's PHP implementation (GNU license)
 * http://www.tecknik.net/sha-1/
 *
 * ...which is based on Paul Johnston's JavaScript version
 * (BSD license). http://pajhome.org.uk/
 *
 * I encapsulated the functions and wrote one additional method to fix
 * a hex conversion bug. - Rick Ellis
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Encryption
 * @author		ExpressionEngine Dev Team
 * @link		http://codeigniter.com/user_guide/general/encryption.html
 */
class CI_SHA1 {
	
	public function __construct() {
		log_message ( 'debug', "SHA1 Class Initialized" );
	}
	
	/**
	 * Generate the Hash
	 *
	 * @access	public
	 * @param	string
	 * @return	string
	 */
	function generate($str) {
		$n = ((strlen ( $str ) + 8) >> 6) + 1;
		
		for($i = 0; $i < $n * 16; $i ++) {
			$x [$i] = 0;
		}
		
		for($i = 0; $i < strlen ( $str ); $i ++) {
			$x [$i >> 2] |= ord ( substr ( $str, $i, 1 ) ) << (24 - ($i % 4) * 8);
		}
		
		$x [$i >> 2] |= 0x80 << (24 - ($i % 4) * 8);
		
		$x [$n * 16 - 1] = strlen ( $str ) * 8;
		
		$a = 1732584193;
		$b = - 271733879;
		$c = - 1732584194;
		$d = 271733878;
		$e = - 1009589776;
		
		for($i = 0; $i < count ( $x ); $i += 16) {
			$olda = $a;
			$oldb = $b;
			$oldc = $c;
			$oldd = $d;
			$olde = $e;
			
			for($j = 0; $j < 80; $j ++) {
				if ($j < 16) {
					$w [$j] = $x [$i + $j];
				} else {
					$w [$j] = $this->_rol ( $w [$j - 3] ^ $w [$j - 8] ^ $w [$j - 14] ^ $w [$j - 16], 1 );
				}
				
				$t = $this->_safe_add ( $this->_safe_add ( $this->_rol ( $a, 5 ), $this->_ft ( $j, $b, $c, $d ) ), $this->_safe_add ( $this->_safe_add ( $e, $w [$j] ), $this->_kt ( $j ) ) );
				
				$e = $d;
				$d = $c;
				$c = $this->_rol ( $b, 30 );
				$b = $a;
				$a = $t;
			}
			
			$a = $this->_safe_add ( $a, $olda );
			$b = $this->_safe_add ( $b, $oldb );
			$c = $this->_safe_add ( $c, $oldc );
			$d = $this->_safe_add ( $d, $oldd );
			$e = $this->_safe_add ( $e, $olde );
		}
		
		return $this->_hex ( $a ) . $this->_hex ( $b ) . $this->_hex ( $c ) . $this->_hex ( $d ) . $this->_hex ( $e );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Convert a decimal to hex
	 *
	 * @access	private
	 * @param	string
	 * @return	string
	 */
	function _hex($str) {
		$str = dechex ( $str );
		
		if (strlen ( $str ) == 7) {
			$str = '0' . $str;
		}
		
		return $str;
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Return result based on iteration
	 *
	 * @access	private
	 * @return	string
	 */
	function _ft($t, $b, $c, $d) {
		if ($t < 20)
			return ($b & $c) | ((~ $b) & $d);
		if ($t < 40)
			return $b ^ $c ^ $d;
		if ($t < 60)
			return ($b & $c) | ($b & $d) | ($c & $d);
		
		return $b ^ $c ^ $d;
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Determine the additive constant
	 *
	 * @access	private
	 * @return	string
	 */
	function _kt($t) {
		if ($t < 20) {
			return 1518500249;
		} else if ($t < 40) {
			return 1859775393;
		} else if ($t < 60) {
			return - 1894007588;
		} else {
			return - 899497514;
		}
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Add integers, wrapping at 2^32
	 *
	 * @access	private
	 * @return	string
	 */
	function _safe_add($x, $y) {
		$lsw = ($x & 0xFFFF) + ($y & 0xFFFF);
		$msw = ($x >> 16) + ($y >> 16) + ($lsw >> 16);
		
		return ($msw << 16) | ($lsw & 0xFFFF);
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Bitwise rotate a 32-bit number
	 *
	 * @access	private
	 * @return	integer
	 */
	function _rol($num, $cnt) {
		return ($num << $cnt) | $this->_zero_fill ( $num, 32 - $cnt );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Pad string with zero
	 *
	 * @access	private
	 * @return	string
	 */
	function _zero_fill($a, $b) {
		$bin = decbin ( $a );
		
		if (strlen ( $bin ) < $b) {
			$bin = 0;
		} else {
			$bin = substr ( $bin, 0, strlen ( $bin ) - $b );
		}
		
		for($i = 0; $i < $b; $i ++) {
			$bin = "0" . $bin;
		}
		
		return bindec ( $bin );
	}
}
// END CI_SHA

/* End of file Sha1.php */
/* Location: ./system/libraries/Sha1.php */